1. Field of the Invention
The invention relates to a hydrostatic drive train for a vehicle, and more particularly to the mounting and drive arrangement of the hydrostatic pumps employed in the hydrostatic drive transmission.
2. Prior Art
In the past, efforts to employ hydrostatic drive on a vehicle have often been directed towards simply replacing the conventional drive transmission of the vehicle with a hydrostatic drive. As a result, the hydrostatic pumps, motors and controls were located in a modified final drive case where they were inaccessible for adjustment and servicing.
Other past efforts have lead to the provision of a noncomplex and economical hydrostatic drive system for a vehicle in which the hydrostatic pumps are easily accessible and removable for servicing and adjustment. Such a system is taught for example in U.S. Pat. No. 3,797,599 which is assigned to the assignee of the present invention.
One problem which has existed with the prior art pump drive has been that the mechanical drive part thereof, i.e., the gears, have not always been sufficiently accessible for easy servicing and replacement. Further, in many instances, the gears which drive the hydrostatic pumps in the prior art apparatus have been located between the pumps whereby relatively complex null and gain control linkages have been needed to assure that the displacements of the hydraulic pumps can be simultaneously controlled.
Accordingly, it is an object of the present invention to provide an improved vehicle having hydrostatic pump means wherein the gears which drive said pump means are located externally of a compartment structure which houses said pump means.
It is a further object of the invention to provide a vehicle wherein relatively simple null and gain control linkage can be utilized.
These and other objects of the invention which will become apparent from reading the following description are accomplished as described in following.